Radiation fin, cooling device, electronic equipment, and manufacturing method of cooling device

ABSTRACT

Each of fins is provided with an engage projection having a first width and a engage hole portion having a second width wider than the first width, and the fins are able to be slid while engaging with each other. Accordingly, in case of installing a heat sink to a case of a fan, it is possible to install the fins to the case so that the fins are arranged in a flowing direction of a refrigerant by the fan while engaging with each other. As the result, the refrigerant is able to flow smoothly when passing through the fins by arranging the fins at desired angle. Accordingly, it becomes possible to present a radiation fin, a cooling device and an electronic equipment having such cooling device.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional Application of the patentapplication No.: 10/994,456, filed Nov. 23, 2004, now U.S. Pat. No.7,165,601, issued Jan. 23, 2007, which claims priority from Japaneseapplication No. 414322 filed on Dec. 12, 2003, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a radiation fin for radiating heatgenerated from a heating element, a cooling device equipped with aradiation fin, electronic equipment equipped with a cooling device, anda manufacturing method of a cooling device.

2. Description of Related Art

As a device for cooling a heating element, such as a central processingunit (CPU), there has heretofore been proposed a heat sink such as aradiation fin. In a heat sink, heat radiation thereof is hastened by airblown by a fan, for example.

This heat sink is constructed by stacking a plurality of fin members.Specifically, a claw portion and an engage hole are respectivelydisposed in the individual fins, and the heat sink is constructed byattaching plural fins to a fan case, or the like in the state in whichthe claw portions of the respective fins are engaged with the engageholes of the adjacent fins (for example, see a patent document 1:Japanese Laid-Open Patent No. 2002-314009).

However, for example, when a heat sink 205 described in the PatentDocument 1 is attached to an air outlet 203 a of a case 203 of a fan 210as shown in FIG. 20, the following problems arise. For example, the flowof air generated by the rotation of an impeller 206 disposed in the fancase 203 has a certain angle to the longitudinal direction of the heatsink 205, and hence the air cannot flow through smoothly between therespective fins 202 of the heat sink 205. This causes not only a drop ina heat radiation efficiency, but also the drawback of becoming a noisesource because the air is blown with the certain angle to the respectivefins 202.

In addition, for example, to achieve that the flow of air generated bythe impeller 206 can pass through smoothly between the respective fins202, it is necessary to fix the heat sink 205 so as to be offsetrightward when viewed, in the figure, from a rotation center P of theimpeller 206 as shown in FIG. 21. This has the disadvantage that acooling device itself becomes larger, and this is not fit forminiaturization.

To solve these problems, there is a cooling device in which the heatradiation is done by smoothly passing the air generated by a fan withthe use of a heat sink 207 that is given a curvature after beingconstructed by stacking fins 208, as shown in FIG. 22. To curve the heatsink 207, however, equipment and a jig for making an angle are required,which causes a cost increase.

SUMMARY OF THE INVENTION

In view of the foregoing circumstances, one of the aspects of thepresent invention is to provide a radiation fin that is able to increasea heat radiation efficiency or a cooling efficiency, and is high incooling performance, as well as a cooling device, and an electronicequipment equipped with this cooling device.

Another aspect of the present invention is to provide a radiation finthat is able to reduce noise and to achieve miniaturization, a coolingdevice, and an electronic equipment equipped with this cooling device.

Another aspect of the present invention is to provide a manufacturingmethod of a cooling device, by which it is able to easily manufacture aradiation fin, and a cooling device equipped with a radiation fin.

A radiation fin of the present invention is a radiation fin that isequipped with a plurality of fins, each of which includes a plurality ofengage projections disposed having a first width, and a plurality ofengage hole portions that is disposed having a second width greater thanthe aforesaid first width, wherein it is possible for the engage holeportions to engage with the aforesaid engage projections of an adjacentfin.

In the present invention, the engage hole portions having the secondwidth greater than the first width of the engage projections aredisposed at each of the fins. Therefore, for example, the fins can beslid with each other while engaging with each other. Thereby, forexample, when the radiation fin is attached to a case of the fan, etc.,the fins can be attached so as to position along the direction ofrefrigerant flow through the fan, that is, obliquely at an arbitraryangle to the case, while the fins are being slid over each other. As aresult, since the resistance when the refrigerant flow passes throughbetween the respective fins can be reduced, the refrigerant flowssmoothly to allow for improvement in the heat radiation efficiency.Additionally, noise can be reduced because the refrigerant flowssmoothly between the respective fins. Further, miniaturization of theheat sink is attainable because there is no need for offsetting theinstallation position of the radiation fin with respect to the case, ashas been conventional.

In accordance with one embodiment of the present invention, each of theaforesaid engage projections has flexibility. This facilitates easyengagement of the engage projection with the engage hole portion andalso prevents to the utmost the respective fins from separating fromeach other.

In accordance with one embodiment of the present invention, theaforesaid engage projection has a surface in the shape of a curvedsurface or in the shape of a slant surface such that its height changesin substantially the width direction of the aforesaid first or secondwidth. This facilitates the easy engagement of the engage projectionwith the engage hole portion.

In accordance with one embodiment of the present invention, each of theaforesaid fins includes an abutment projections that is disposed at theaforesaid engaged hole portion to lock the aforesaid respective finswith each other while engaging the aforesaid engage projections with theaforesaid engage hole portion. This enables easy engagement of therespective fins with each other in a first or second width direction,namely a slide direction, thereby preventing to the utmost therespective fins from separating from each other.

In accordance with one embodiment of the present invention, a pluralityof the aforesaid abutment projections are disposed at each of theaforesaid fins. This allows for stepwise slide with the respective finsengaged to each other. Therefore, the array angle of the respective finscan be adjusted suitably and stepwise. As a result, for example, whenthe radiation fin is attached to a case of a fan, the angle of theradiation fin to the case can be adjusted suitably and stepwise.

In accordance with one embodiment of the present invention, each of theaforesaid abutment projections has a surface in the shape of a curvedsurface or in the shape of slant surface such that the height changes insubstantially the width direction of the aforesaid first or secondwidth. Thereby, when the angle of an array direction is adjusted byhaving the respective fins slide over each other, it is easy to havethem slide.

In accordance with one embodiment of the present invention, each of theaforesaid respective fins has a plurality of bent regions that is bentin a predetermined length from each end portion, and each of theaforesaid engage projections is disposed so as to project outwardly fromthe aforesaid end portion, and each of the aforesaid engage holeportions is disposed at the aforesaid bent region. Alternatively, inaccordance with one embodiment of the present invention, each of theaforesaid respective fins has a plurality of bent regions that is bentin a predetermined length from each end portion, and the aforesaidengage projection is disposed so as to project at a bending position ofthe bend region, and the aforesaid engage hole portion is disposed atthe bent region. By disposing this bent region, the invention is able toform a predetermined spaced interval between the respective fins andfurther maintain satisfactorily the engage state between the respectivefins.

A cooling device in accordance with the present invention includes acase having a suction port and an exhaust port, an impeller member thatis encased in the aforesaid case and can exhaust refrigerant sucked intothe aforesaid case via the aforesaid suction port in a first directionto outside of the aforesaid case via the aforesaid exhaust port, and aplurality of first fin groups that are arranged in the vicinity of theaforesaid exhaust port and are attached to the aforesaid case such thattheir respective surfaces are oriented in the aforesaid first directionand obliquely to the direction of arrangement.

In the present invention, the surface of each fin of the first fingroups are attached to the case so as to be oriented in the firstdirection and obliquely to the direction of arrangement. This enables areduction in the resistance when the flow of refrigerant from theimpeller member passes through between the respective fins, so that therefrigerant flows smoothly to allow for an improvement in the heatradiation efficiency. Additionally, noise can be reduced because therefrigerant flows smoothly between the respective fins. Further,miniaturization of the cooling device is attainable because there is noneed for offsetting the installation position of the radiation fin withrespect to the case, as has been conventional.

In accordance with one embodiment of the present invention, theaforesaid impeller member further includes a plurality of second fingroups, which can exhaust the aforesaid refrigerant in a seconddirection different from the aforesaid first direction, and arrangedwith plural number in the vicinity of the aforesaid exhaust port, andwhich are attached to the aforesaid case such that their respectivesurfaces are oriented in the aforesaid second direction. For example,depending on the shape, the size and the like of the impeller member orthe case, the exhaust direction of refrigerant exhausted from theexhaust port may be different for different locations. In other words,the refrigerant may be exhausted in the first direction and the seconddirection, and hence by disposing the first fin groups and the secondfin groups in response to this, the heat radiation efficiency or thecooling efficiency can be further improved.

A cooling device according to another viewpoint of the present inventionincludes a case having a suction port and an exhaust port, an impellermember that is encased in the aforesaid case and can exhaust refrigerantsucked into the aforesaid case via the aforesaid suction port to outsideof the aforesaid case via the aforesaid exhaust port, and a plurality offins which are disposed in the vicinity of the aforesaid exhaust portand are attached to the aforesaid case such that their directions arevariable depending on an exhaust direction of the aforesaid refrigerant.

Since in the present invention a plurality of the fins are attached tothe aforesaid case such that their directions are variable depending onthe exhaust direction of refrigerant, the refrigerant flows smoothly andheat dissipation efficiency can be improved. Additionally, noise can bereduced because the refrigerant flows smoothly between the respectivefins. Further, miniaturization of the cooling device is attainablebecause there is no need for offsetting the installation position of theradiation fin with respect to the case, as has been conventional. Forexample, the aforesaid respective fins are variable in their directionssuch that their respective surfaces are directed in the aforesaidexhaust direction.

An electronic equipment according to the present invention is anelectronic equipment, which is provided with a radiation fin in which aplurality of fins are arranged and disposed, and which has a heatingelement, a case having a suction port and an exhaust port, a fan that isencased in the aforesaid case and has an impeller member which canexhaust refrigerant sucked into the aforesaid case via the aforesaidsuction port in a predetermined direction to outside of the aforesaidcase via the aforesaid exhaust port, engage projections respectivelydisposed in a first width at the aforesaid respective fins, and engagehole portions that are respectively disposed in a second width greaterthan the aforesaid first width at the respective fins and can be engagedto the aforesaid engage projections of adjacent fins, and the surfacesof the aforesaid respective fins are attached to the aforesaid case soas to be oriented in the aforesaid predetermined direction and obliqueto an array direction, in order to dissipate the heat of the aforesaidheating element.

In the present invention, cooling treatment of a heating element to bemounted on an electronic equipment can be performed efficiently. As aheating element, an electronic equipment, such as IC chips andresistors, or a radiation fin, etc. may be cited. However, withoutlimiting to these, an electronic equipment may be anything whichgenerates heat. As an electronic equipment, computers, personal digitalassistances (PDAs), and other electrical appliances, etc. may be cited.The same is true for the following.

A manufacturing method of a cooling device in accordance with thepresent invention is a manufacturing method of a cooling device, whichhas a case having a suction port and an exhaust port, an impeller memberthat is encased in the aforesaid case and can exhaust refrigerant suckedinto the aforesaid case via the aforesaid suction port in apredetermined direction to outside of the aforesaid case via theaforesaid exhaust port, and a plurality of fins arranged and disposed inthe vicinity of the aforesaid exhaust port, including, a step ofengaging engage projections disposed respectively in a first width atthe aforesaid fins to engage hole portions of adjacent fins that aredisposed in a second width greater than the aforesaid first width at theaforesaid respective fins, a step of sliding the respective fins overeach other with the respective engage projections engaged to therespective engage hole portions, and a step of attaching to theaforesaid case such that the surfaces of the aforesaid respective slidfins are oriented in the aforesaid predetermined direction and areoblique to an array direction.

Traditionally, to attach obliquely a radiation fin to a case as in thepresent invention, it is necessary to attach obliquely individual finsto the case. However, in the present invention the angle of individualfins can be set obliquely to the array direction of the respective finsonly by having the respective fins slide over each other when theradiation fin is attached to a fan case. Therefore, after having themslide, the radiation fin can be attached to the case thereby tofacilitate manufacturing.

Thus, in accordance with the present invention, the heat radiationefficiency or cooling efficiency can be improved, noise can be reduced,and miniaturization is attainable. In addition, a radiation fin and acooling device equipped with a radiation fin can be manufactured easily.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a fin in accordance with onepreferred embodiment of the present invention;

FIG. 2 is a perspective view showing a heat sink assembled by stacking aplurality of fins;

FIG. 3 is a sectional view taken along the line A-A in FIG. 2;

FIG. 4 is a plan view showing a heat sink with the respective fins slid;

FIG. 5 is a perspective view of the heat sink shown in FIG. 4;

FIG. 6 is a plan view showing a cooling device in which the heat sinkwith the respective fins slid is attached to a fan;

FIG. 7 is a plan view showing a modification of the cooling device shownin FIG. 6;

FIG. 8 is a perspective view showing a cooling device in accordance withanother preferred embodiment of the present invention;

FIG. 9 is a perspective view from the backside of the cooling deviceshown in FIG. 8;

FIG. 10 is a perspective view showing the state in which a cover isremoved from the case of the cooling device shown in FIG. 8;

FIG. 11 is an enlarged perspective view showing an engage location of afin in accordance with another preferred embodiment;

FIG. 12 is a perspective view showing the state in which the fins shownin FIG. 11 are stacked;

FIG. 13 is a perspective view showing a modification of the fins shownin FIG. 12;

FIG. 14 is an enlarged perspective view showing an engage location of afin in accordance with still another preferred embodiment;

FIG. 15 is a sectional view taken along the line B-B in FIG. 14;

FIG. 16 is a perspective view showing part of a heat sink in accordancewith still another preferred embodiment;

FIG. 17 is a perspective view showing a rail for allowing a pin to beremoved;

FIG. 18 is a plan view showing the state in which the heat sink shown inFIG. 16 is attached to a fan;

FIG. 19 is a plan view showing the state in which air flow is blownagainst the heat sink;

FIG. 20 is a plan view showing a conventional cooling device;

FIG. 21 is a plan view showing another conventional cooling device; and

FIG. 22 is a plan view showing another conventional cooling device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described belowbased on the drawings.

FIG. 1 is a perspective view showing a fin in accordance with onepreferred embodiment of the present invention. A fin 10 is constructedby bending in a predetermined length from its end portion 6, and havinga bent region 3. Herein, the predetermined length depends on the size ofthe fin 10, and should not be limited. For example, it may be 5 to 20%of a height direction of the fin 10 (the Z direction). The bent regions3 are disposed at two locations. The end portion 6 is provided withengage projections 4, which may be four pieces, for example. The engagehole portions 2, which may be four pieces, for example, are disposed inthe vicinity of the respective engage projections 4. A width s of theengage hole portion 2 is greater than a width t of the engage projection4. Specifically, it is able to be formed so as to be, for example, s=2tto 5t, without being limited to this. The values of t and s areapproximately the same in the four engage projections 4 and the fourengage hole portions 2, respectively.

While metal such as copper and aluminum, etc. can be used as thematerial of the fin 10, without limiting to these, high-thermalconductance fibers, such as carbon may be used.

FIG. 2 is a perspective view showing a heat sink as a radiation fin,which is assembled by stacking a plurality of fins 10. FIG. 3 is asectional view taken along the line A-A in FIG. 2. As shown in FIG. 2and FIG. 3, the engage projections 4 are engaged to the engage holeportions 2 of the adjacent fins 10, and the respective fins 10 arearranged and stacked with the respective surfaces 5 of the fins 10disposed substantially parallel with each other.

FIG. 4 and FIG. 5 are a plan view and a perspective view, respectively,showing the state in which the respective fins 10 are slid when a heatsink 20 so constructed is attached to a fan. Having them so slide ispossible because the width s of the engage hole portion 2 is greaterthan the width t of the engage projection 4, as described above. FIG. 6is a plan view showing a cooling device in which the heat sink 20 withthe respective fins 10 so slid is attached to a fan 21. The heat sink isable to be attached so as to be oriented in the direction of refrigerantflow through an impeller 26, that is, obliquely to a case 23, with therespective fins 10 slid over each other. Specifically, the heat sink isable to be attached such that the surfaces 5 of the fins 10 are orientedin the direction in which refrigerant is exhausted, and such that thesurfaces 5 are set obliquely to the array direction of the fins 10 (theX direction), for example. As attaching means, heat welding, thermocompression bonding, or soldering, etc. may be employed. As refrigerant,air may be cited, for example.

Since the resistance when refrigerant passes through between therespective fins 10 can be reduced in this preferred embodiment, therefrigerant flows smoothly, and the heat radiation efficiency of theheat sink 20 or the cooling efficiency of a cooling device 30 can beimproved. Additionally, noise can be reduced because the refrigerantflows smoothly between the respective fins 10. Further, miniaturizationof the fan 21 is attainable because there is no need for offsetting theinstallation position of a heat sink 205 with respect to a case 204, asin a conventional manner shown in FIG. 21.

FIG. 7 is a plan view showing a modification of the cooling device 30shown in FIG. 6. A fan 31 of a cooling device 40 has a case 33 of ashape different from that of the case 23 in the fan 21 shown in FIG. 6.In the case 33, the passage of refrigerant in the inside thereof iswidened on the right side when viewed in the figure, as compared to thecase 23 shown in FIG. 6. The refrigerant is exhausted substantiallylinearly from an exhaust port 33 a as indicated by reference numeral 28,at the location at which the passage is widened. It is exhaustedobliquely at the location indicated by reference numeral 29. To complywith these different two exhaust directions, a first fin group 45disposed in an oblique direction to the exhaust port 33 a and a secondfin group 46 disposed in an orthogonal direction are attached to thecase 33. Since the exhaust direction of refrigerant exhausted from theexhaust port 33 a might be different for different locations, dependingon the shape and the size of the impeller 26 and the case 33, a heatradiation efficiency or a cooling efficiency can be further improved bythe forgoing construction of this preferred embodiment.

FIG. 8 is a perspective view showing a cooling device in accordance withanother preferred embodiment of the present invention. FIG. 9 is aperspective view from the backside of this cooling device. A coolingdevice 50 in accordance with this preferred embodiment is constructed byrotatably encasing an impeller 56 within a housing 59. The impeller 56is rotatable by a motor (not shown), or the like. The housing 59 has acase 53, and a cover 57 attached to an upper part of the case 53. FIG.10 is a perspective view showing the cooling device 50 with the cover 57removed from the case 53. Formed in the case 53 is an opening 53 a,through which the air in the outside is introduced into the inside ofthe case 53 via a suction port 57 a disposed in the cover 57. Inaddition, for example, two exhaust ports 53 b and 53 c are formed in thecase 53, and heat sinks 20A and 20B are attached obliquely to theexhaust ports 53 b and 53 c, respectively.

As for the case 53 and the cover 57, high-thermal conductance materialmay be used. Specifically, it is possible to use metal such as aluminumand copper, or carbon fiber that permits lightening, and the like.

A plate member 54 for heat radiation is integrally disposed in the case53, and a heat spreader 55 is attached to the backside of the platemember 54, as shown in FIG. 9. For example, a CPU (not shown) is bondedto the heat spreader 55 with heat conductive adhesive etc. Thin typeheat pipes 52A and 52B are attached to the plate member 54, and the heatsinks 20A and 20B. In the heat pipe 52A, a heat absorbing portionthereof is attached to the plate member 54, and a heat radiation portionthereof is attached to the heat sink 20A. In the heat pipe 52B, a heatabsorbing portion thereof is attached to the plate member 54, and a heatradiation portion thereof is attached to the heat sink 20B.

The operation of the cooling device 50 so constructed will be described.If the CPU (not shown) generates heat, the heat is conducted via theheat spreader 55 and the plate member 54 to the heat pipes 52A and 52B.The heat is transmitted to the heat sinks 20A and 20B by the heat pipes52A and 52B, respectively, and then dissipated by the heat sinks 20A and20B. Further, by the rotation of the impeller 56, air is introduced fromoutside to the inside of the housing 59, and the air is exhaustedthrough exhaust ports 53 b and 53 c. This facilitates heat radiationaction of the heat sinks 20A and 20B.

A manufacturing method of the cooling device 50 will be described next.Particularly, a method of attaching the heat sinks 20A and 20B to thecase 53 is described mainly.

In the heat sinks 20A and 20B, the respective fins 10 are formed by diepressing, etc., and then ejected from a manufacturing device (notshown), with the respective fins 10 stacked, namely as the heat sinks20A and 20B. Subsequently, in the heat sinks 20A and 20B, the respectivefins 10 are slid by the hands of an operator or by a device (not shown).In the slid state, namely, in the state shown in FIG. 4 or FIG. 5, theyare attached to the exhaust ports 53 b and 53 c of the case 53 by thehands of an operator or a device (not shown). The heat sinks 20A and 20Bcan be fixed to the case 53 by, for example, heat welding, thermocompression bonding, or soldering, etc. Thereafter, the heat pipes 52Aand 52B are attached, and the cover 57 is attached.

In this preferred embodiment, the heat sinks 20A and 20B can be attachedobliquely at an arbitrary angle to the case 53. Therefore, therefrigerant flow passes through smoothly between the respective fins 10,and the heat radiation efficiency of the heat sink 20 or the coolingefficiency of the cooling device 30 can be improved, and noise can bereduced.

Additionally, to attach the heat sink 20A, etc. obliquely to the case 53as in this preferred embodiment, traditionally, it is necessary toattach obliquely individual fins to a case. However, in this preferredembodiment the angle of the respective fins can be set obliquely to thearray direction of the respective fins only by having the respectivefins such as the heat sink 20A, etc. slide over each other. Therefore,after having them slide, the heat sink 20A, etc. can be attached to thecase 53, thereby to facilitate manufacturing.

FIG. 11 is an enlarged perspective view showing engage locations of finsin accordance with another preferred embodiment. Four engage holeportions 62 are disposed in a bent region 63 of a fin 60 in accordancewith this preferred embodiment, and four engage projections 64 also aredisposed at end portions. In FIG. 11, only one engage hole portion 62and one engage projection 64 are shown, and others are omitted. In theengage hole portion, an abutment projection 68 projecting upwardly isformed at the side surface of the fin. While there are disposed forexample, two abutment projections 68, without limiting to this, theremay be three or more pieces.

When the fins 60 shown in FIG. 11 are stacked, namely, when the engageprojection 64 of one fin 60 is engaged to the engage hole portion 62 ofother fin 60, as shown in FIG. 12, the engage projection 64 abuts theabutment projection 68. This prevents the fins 60 from sliding orseparating from each other. For example, when a heat sink is attached toa fan case, the heat sink can be attached easily to the case whilereliably maintaining the slide state, namely retaining the rigidity ofthe heat sink. In addition, by disposing two or more abutmentprojections 68, the angles of the fins 60 can be adjusted stepwise,thereby optimizing a cooling efficiency.

FIG. 13 is a perspective view showing a modification of the fin shown inFIG. 12. A fin 70 has a rectangular abutment projection 78 at an engagehole portion 72. This fin 70 also has an engage projection 74, and anopening 74 a is formed in the engage projection 74. It is constructedsuch that the abutment projection 78 of another fin 70 engages to theopening 74 a. This enables a plurality of the fins 70 to be engaged toeach other and also prevents the fins 70 from sliding over each other.The abutment projection 78 should not be limited to the rectangularshape, and it may be of a triangular shape as shown in FIG. 12, or ashape having a curved surface.

FIG. 14 is an enlarged perspective view showing an engage location of afin in accordance with still another preferred embodiment. FIG. 15 is asectional view taken along the line B-B in FIG. 14. An engage projection84 of a fin 80 is disposed so as to project upwardly at the bendingposition of a bent region 83. An engage hole portion 82 disposed in agreater width than the width of the engage projection 84 is formed atthe bent region 83. With this construction, the fins 80 can be slid soas to have an arbitrary angle. A plurality of the engage hole portions82 may be disposed in the width direction.

FIG. 16 is a perspective view showing part of a heat sink in accordancewith still another preferred embodiment. In fins 90 of a heat sink 100,holes 98, through which pins 95 are inserted, are formed in the vicinityof the ends of bent regions 93, respectively, and an ellipse hole 99 isformed in the vicinity of the end of the bent region 93 of the fin 91 atthe right end when viewed in the figure. The pins 95 are disposed inorder to attach to a case 103 of a fan 110, as shown in FIG. 18. Inother words, two pins 95 are respectively disposed vertically at bothends in the vicinity of an exhaust port 103 a of a case 103, and the twopins 95 are inserted through the holes 98 and 99 of the fins at bothends of a heat sink 100, so that the heat sink 100 is attached to thecase 103. The respective fins 90 sandwiched between the fins 90 and 91at both ends are mutually in an engage state, and hence in the absenceof the pin 95, they do not mutually come off the case 103.

The diameter of the hole 98 is formed slightly greater than the size ofthe pin 95 (the diameter of cross section), so that the fin 90 is freelyrotatable relative to the pin 95. Thereby, as shown in FIG. 19, the heatsink 100 rotates around the pin 95 and its direction changes so as tofollow the air flow generated by the rotation of an impeller 116. Inother words, the angles of the respective fins 90 are variable inresponse to the air flow.

Herein, the relationship between the width a of the heat sink 100 beforethe respective fins 90 are slid (see FIG. 18), and the width b of theheat sink 100 after they are slid (see FIG. 19) is indicated by a<b.Therefore, as shown in FIG. 17 and FIG. 18, a rail 105 may be disposedin the case 103 such that the pin 95 at the right end is removable rightand left when viewed in the figure. Alternatively, when the travelamount of the heat sink 100 is small, even in the absence of the rail105, the fin 91 is removable in the longitudinal direction of theellipse hole 99 by the presence of the ellipse hole 99. Thisconstruction of the cooling device permits a further improvement in acooling efficiency, and permits a reduction in noise.

The present invention should not be limited to the foregoing preferredembodiments, and various modifications are possible.

While the engage projections 4, 64, 74, and 84 in the respectiveforegoing preferred embodiments are in the rectangular shape, they maybe of a shape having a curved surface, or a polygon shape, namely aslope shape. Alternatively, the engage projections 4, 64, 74, and 84 maybe made of material having flexibility. Flexibility is realizable byhaving the engage projections have resiliency or by using rubber. Thepossession of flexibility facilitates the engagement of the engagedprojections to the engage hole portions and also prevents to the utmostthe respective fins from separating from each other.

While in FIG. 16, the invention is constructed to dispose the ellipsehole 99 only at the right end fin 91, it may be constructed to disposethe ellipse hole 99 at the respective fins in order to make all of therespective fins the same article. As a result, the productivity of thefins is improved. In addition, when a heat sink composed of these finsis attached to a fan case, the respective fins can be oriented obliquelyand smoothly.

For example, the embodiments illustrated in the respective figures maybe suitably combined to construct a fin, a heat sink, a cooling device,an electronic equipment, etc.

1. A cooling device comprising: a case having a suction port and anexhaust port; an impeller member that is encased in the case to exhaustrefrigerant sucked into the case via the suction port in a firstdirection to outside of the case via the exhaust port; and a pluralityof first fin groups that are arranged in the vicinity of the exhaustport and are attached to the case such that their respective surfacesare oriented in the first direction and obliquely to the direction ofarrangement, fins of said first fin group each including an abutmentprojection that is disposed at an engage hold portion to lock saidrespective fins to each other while engaging an engage projection withsaid engage hole portion, wherein: each of said fins of said first groupincludes a plurality of engage projections having a first width, and aplurality of said engage hole portions having a second width wider thanthe first width, and is able to engage with said engage projections ofan adjacent fin.
 2. The cooling device as cited in claim 1, furthercomprising: a plurality of second fin groups, which can exhaust saidrefrigerant in a second direction different from the said firstdirection, and arranged with plural number in the vicinity of saidexhaust port, and which are attached to said case such that theirrespective surfaces are oriented in said second direction.
 3. A coolingdevice comprising: a housing having a suction port and an exhaust port;an impeller member that is encased in the housing to exhaust refrigerantsucked into the housing via the suction port to outside of the housingvia the exhaust port; and a plurality of fins disposed in the vicinityof the exhaust port and are attached to the housing such that theirdirections are variable depending on an exhaust direction of therefrigerant, each of said fins including a plurality of engageprojections disposed in a first width and a plurality of engage holeportions disposed in a second width greater than said first width,wherein said plurality of fins are stacked by engaging said engageprojection with said engage hole portions of the adjacent fin, whereineach of said fins further includes an abutment projection that isdisposed at said engage hole portion to lock said respective fins toeach other while engaging said engage projection with said engage holeportion.
 4. The cooling device as cited in claim 3, wherein; each ofsaid fins varies its direction such that each surface of the fins isarranged in the exhaust direction.